Method of manufacturing brushes



March 1 1927. 1,619,428

H. P. M MILLAN METHOD. OF MANUFACTURING snususs Filed April 23. 1925 Patented ,Mar. 1, 1927 UNITED STATES PATENT OFFICE.

HUGH IE. MCMILLAN, F BALTIMORE, MARY LAND,'ASSIGNOR TO SAMUEL M. DELL & 00., INQ, OF BALTIMORE, MARYLAND, A CORPORATION OF MABYLAND/ METHOD OF MANUFACTURING BRUSHES.

Application filed April 23, 1926. Serial No. 104,154.

This invention relates in general to brushes and their manufacture, and one of the objects of the invention is to provide a new and greatly simplified method of manufac-.

turing certain types of brushes, particularly those brushes in which the bristles are secured in vulcanized rubber.

One of the particular objects of theinvention is to eliminate the present steps of re moving the plug used in the formation of the brush and fitting the handle in the space occupied by the plug; and in place of those steps to allow the plug to remain in the brush and secure the handle directly to the I plug.

7 Another of the particular objects of'the invention is to avoid the necessity of an accurate centering of the plug in the knot; this being effected by forming the handle socket in the plug after the brush has been otherwise completed.

' Another object of the invention is to provide a method by which brushes of the type described herein may be manufactured at'a greatsaving of time, labor, and material.

. Prior to the invention of the method to be described herein, brushes of the type covered by the present invention have been manufactured by a method which was not only slow and expensive, but also resulted in the loss of a great many brushes by loosening the fiber thereof. The method which has bcen'generally employed is well illustrated in the patent to Potter No. 928,401.

7 In accordance with themethod incommon use the bristles are first formed into a bunch; one end of the bunch of bristles is then dipped. into a rubber solution to the desired extent to form the knot. The opposite sides of the bunch are then separated and a plug is inserted in the opening. After the plug has been placed in the knot the bunch of bristles is placed in a drying oven to effect to some extent the hardening of the rubber solution; the knot end of the bristles con taining the wooden or metal plug' is then placed on a heated table until the vulcanization is complete. The plug is then loosened and knocked out; and the handle is inserted The removal of the plug requires considerabl time; but more important than that isthe fact that the bristles often become loos:

ened during the removal of the plug and when that happens the brush is a total loss. In accordance with the present invention the plug is placedin the knot in the manner described above; but instead of removing it later in the process it remains permanently in the knot. p

The idea of permanently mounting the plug in the knot has previously been suggested in the patent to Hugh P. McMillan, No. 1,009,082, November 21, 1911, but in the structure disclosed there a .metal plug was employed and for various reasons the struc ture has been found to be impracticable. It is obvious that in a structure such as shown in McMillian No. 1,009,082, the socket for receiving the handle must be formed in the plug before the plug is inserted in the knot and this being true, it follows that the plug must be very accurately centered with respect to the knot, for otherwise an unbalanced brush would result.

In the present invention applicant employs a wooden plug and he insertsit in the knot without any attempt whatever to ac curately center it with respect to the knot; and then after the brush has been formed a socket to receive the handle is made'in the plug; this socket being centered not with respect to the brush.

It will be clearly understood, from the foregoing description, that the material fea tures of the invention reside in permanently mounting a Wooden plug in the knot, thereby avoiding the necessity of removing the plug before the handle is inserted; and in providing the handle receiving socket in the plug but with respect to the plug after th brush has been otherwise combrush, before the handle receiving socket is provided in the plug.

Figure 2 is a fragmentary perspective view of the brush with the handle receiving socket provided in the plug, and the handle ready to be mounted in the socket; and,

Figure 3 is a. vertical sec-tionalview of the brush, and showing the handle attached thereto.

Referring to the drawings more in detail indicates the bristles.

any preferred method, and are'thentreated with the rubber solution, in the usual manner. The ends of the bristles are thus formed into what is termed a knot, referred to by numeral 2 The plug is indicated numera'l 3; and this plug, in accordance with the'p'resent invention, is now insertedin the knot of'bristles; and the metallic band 4 is secured in place. It will lie-understood that theplug 3 when insert'ed in the knot,has not been provided with the handle receiving socket but has a perfectly plain upper surface, asillustrated in Figure 1.

The rubbermust now be vulcanized, and to accomplish this vulcanization it is only necessary to stand the knot onalieatedtable for the required period of time. An inspection of the drawing will show that the plug, the knot, and the hand, are all in the same plane, and consequently the knot can be applied directly to the table,

After thevulcanization has been com leted the next step is to provide the hand e re ceiving socket 5 in the plug 3. It will be obvious to those skilled in the art that a great deal of time would be required to accurately center a' plug with respect to the knob; and

as-previously stated herein one of the mate'- rial features of the present invention resides in the elimination of the necessity of centering the plug with respect to the knot. In accordance with the present invention the plug is placed in the knot roughly in the center thereof, but no attempt is made to accurately center it audit is immaterial in the present invention whether or not it isaccuratel'y centered. After the brush has been formed as herclnbe'fore described, the center of the brush is determined and the handle receiving socket 5- is made in the plug. Obviously no difiicultyis encountered in locating the center of thebrush and" in making the socket at the center thereof, but the great difficulty would be in accurately centering the plug with respect totheknot.

It will be understood from the foregoing description that if by any chance the plug should be accurately centered in the knot then the handle receiving socket Would be made in the center of the plng,ibut in mostcases the plug'woulcl not by chance he positionedaccurately in' the center of the knot, and in all of such cases the handle receiving These 7 socket would not be in the center of the plug, but might be off center in any direction, though it would always be in the center of the brush. It is immaterial Whether the socket is in the center of the plug for if it is in the center of the brush, that is all that is necessary, for an evenly balancedbrush results.

The socket 5 having been formed in the plug 3 after the bruslrhas been HIOIIIItGd lII the knot, as above-described, all that remains to be done is to insert the handle 6 in the socket, and secure the handle in place by means of a pin 7.

Itwill'be apparent from the foregoing description that I have devised an extremely simple method of manufacturing brushes of this type and it will'also be apparent that there is a great saving of time, labor, and 'material in the practice of the invention.

By the old method, in common practice, the

plug had to be removed, and this involved considerable time, and resulted in the loss of numerous brushes because of the loosening of the bristles during the removal of. the

lug.

Further, while it has been su gested, in the patent to Hugh P. McMillan, cited above, to'employ a permanent plug, yet in accordance with that idea the plug was a metal one and the handle receiving. socket had to be formed in the plug priorto inserting the plug. in thejknota It is obvious,

accor ingly, that to prevent the production ofan unbalancecl' brush itwas essential that the plug be very accurately centered with respect to the knot, and it is apparentto anyone skilled in the art that this is a diflicultthing to do. In the present invention the time and labor involved for centerin the plug with respect to the knot is entirelyeliminated; and applicant employs a wooden plu and provides asocket in the plugafter the' brushihas been formed and merely centers this socket with respect to the brush instead of attempting to center the plug with res set to thebrush. Paving. fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of manufacturing brushes which comprises forming stock into a bunch and treatingit with rubber solutionto form a knot,.1nsertinga plug in the knot, vulcanizing' the rubber, forming a. handle attaching means in the plug while in the'knot, andattaching a handle to the handle attaching means.

2; Themethod of manufacturing brushes which includes forming stockintoa bunch and treating it with a rubber solution to form a knot, inserting a plug in the knot, vulcanizing the rubber, providing the. plug with handle attaching means while in the knot centered with relation tothe brushrather than to the plug, and attaching a handle to the attaching means.

3. The method of manufacturing brushes which includes forming stock into a bunch 5 and treating it With a rubber solution to form a knot, inserting a plug in the knot,

the top of the knot and the top of the plug being in substantially the same plane, vulcanizing the rubber, forming a handle attaching means in the plug While in the knot, 10 the handle attaching means being centered With relation to the brush, and attaching a handle to the handle attaching means.

HUGH P. MoMILLAN. 

